1. Field of the Invention
The present invention relates to an apparatus for attaching and detaching an accessory, such as a lens hood, to and from a front end of a lens barrel.
2. Description of Related Art
In a known photographing lens, an accessory, such as a lens hood or the like, is detachably attached to the front end of a lens barrel to block light which is external to object light from the lens.
A known mechanism for attaching and detaching an accessory to a lens barrel is a bayonet mechanism. The bayonet enables the accessory to be attached to and detached from the lens barrel by rotating the lens barrel. During rotation of the lens barrel, friction occurs between the lens barrel and accessory producing a certain degree of torque (referred to hereinafter as an engagement or a disengagement torque). Owing to this engagement or disengagement torque, an accidental detachment of the accessory, or an accidental movement or oscillation of the accessory after the attachment thereof, are prevented. It is possible to provide a snapping engagement and disengagement mechanism for the accessory.
However, in the known arrangement as discussed above, friction inevitably exists at the sliding portion between the accessory and the lens barrel. This can cause the surface to be scratched or damaged, eventually resulting in an insecure engagement of the accessory due to the decrease in engagement torque. Further, scratches on the sliding surface are not desirable for aesthetic reasons. The decreased engagement or disengagement torque might cause the accessory to be accidentally detached from the lens barrel.